Actually that's not that much considering this was the early 90's. Have you seen "Transformers" (the Michael Bay version)? Most of the CG shots there required 24 hours per frame to render. The scene with the huge worm-like robot fighting Optimus Prime in the 3d movie took 72 hours per frame. And we're talking Industrial Light & Magic's render farm.

They used puppets/robots for most of the close-up shots, but in the really dynamic scenes like this one they used CGI. In fact, the creators were originally going to go 100% practical effects, until some guys showed up and offered to include CG. It turned out so good they used it for many shots.